Short answer
Replace door weather stripping by removing the old material, cleaning the jamb, and installing new weather strip that matches your door style (kerf-in compression bulb, adhesive foam, or V-strip). Measure and cut carefully, start with the top, then the latch side, then the hinge side, and finally adjust or replace the door sweep/threshold. Test for proper seal using a dollar-bill test and adjust until the door closes smoothly with even compression.
Why it matters and what to use
Good weather stripping stops drafts, reduces energy bills, and keeps dust/pests out. On most exterior doors, the best performer is a kerf-in compression bulb strip that pushes into a groove (kerf) in the door jamb. Older doors may use adhesive-backed foam or V-strip (spring bronze or vinyl) on the stop. You’ll likely also need to check the bottom seal (door sweep) and threshold.
Common types
- Kerf-in compression bulb (most modern doors): Push-in strip with T-shaped barb that fits the jamb groove
- Adhesive foam tape: Quick fix, good for interior doors or temp repairs
- V-strip (spring bronze or vinyl): Durable and traditional, nails or adhesive under the stop
- Door sweep: Attaches to the bottom of the door (brush or rubber fin)
Typical specs
- Door gap target after install: 1/16"–1/8" uniform
- Kerf width: ~1/8"–3/16" (match existing)
- Bulb compression: about 25–50% when door is closed
Tools and materials
- Replacement weather stripping (match type/kerf size and color)
- Door sweep (if needed) and screws
- Measuring tape and pencil
- Utility knife or miter shears; scissors for vinyl
- Putty knife or small pry bar (to remove old strips)
- Adhesive remover or mineral spirits, rags
- Speed square for clean 45° corners
- Screwdriver or drill/driver
- Rubber mallet (for kerf-in seating)
- Safety glasses and cut-resistant gloves
- Optional: hair dryer/heat gun on low to soften old adhesive
Cost/time: Expect $10–$40 for perimeter strips, $10–$30 for a sweep, and 30–90 minutes for a standard door.
Step-by-step
1) Identify your system
- Open the door and inspect the jamb. If you see a narrow groove with a T-shaped strip pressed in, you have kerf-in. If the strip is stuck to the stop with adhesive or tiny nails, you have foam or V-strip.
- Check the bottom seal and threshold for wear and daylight.
2) Remove old weather stripping
- Kerf-in: Pull from a corner and work along the length. Use a putty knife if it’s stubborn.
- Adhesive/V-strip: Gently pry or peel. Soften adhesive with heat if needed. Remove residue with mineral spirits. Let it dry fully.
3) Clean and prep
- Vacuum dust and debris. Ensure the jamb and stop are smooth and dry. Tighten any loose stop molding.
- If the door rubs or is out of square (uneven gaps), address hinge screws and alignment first; weather stripping won’t fix a crooked door.
4) Measure and cut
- Measure the head (top) first. Cut the new strip slightly long and test-fit.
- For kerf-in bulb: Seat the barb into the kerf starting at one end, pressing in with thumbs or a rubber mallet. Do not stretch the strip; let it sit naturally.
- Cut clean, square ends or miter at 45° where the head meets the sides for a neat corner.
5) Install in order
- Top first, then latch side, then hinge side. This order helps the door latch smoothly and creates even compression.
- Adhesive foam/V-strip: Mark placement, dry-fit with the door, then peel and stick or nail lightly. Close the door to confirm compression before final pressing/nailing.
6) Door sweep and threshold
- Remove the old sweep from the bottom edge. Close the door and mark the desired sweep contact with the threshold (light contact, not dragging).
- Install the new sweep level, starting with center screw slots to allow adjustment. Trim ends as needed.
- If you see daylight under the door even with a new sweep, adjust or replace the threshold gasket or the threshold height (many have adjustment screws).
7) Test and adjust
- Dollar-bill test: Close the door on a bill at several points. You should feel moderate resistance when pulling it out, consistently around the perimeter.
- Ensure the door closes and latches without excessive force. If it’s too tight, try a smaller bulb size or reposition foam/V-strip slightly outward.
Safety
- Wear gloves and eye protection when cutting or prying.
- Use a sharp blade and cut away from your body.
- Be cautious with heat on painted surfaces; older paint may contain lead—avoid sanding and create minimal dust.
- Use a stable step stool if you need height.
Tips for best results
- Match the kerf size and bulb size to your door. Bring a small piece of the old strip to the store.
- Warm adhesive-backed foam indoors before applying; it sticks better above 50°F.
- Don’t stretch foam or kerf-in strips during install—they’ll shrink and leave gaps later.
- For metal doors/frames, use manufacturer-recommended magnetic or kerf-in seals.
- Color-match for a clean look; white, brown, and tan are common.
- If drafts persist at the latch, check for loose strike plate screws or sagging hinges—tighten hinge screws into the framing with 3" screws.
Common mistakes
- Choosing the wrong profile or bulb size, leading to a door that won’t latch.
- Cutting too short—always sneak up on the length; you can trim more but can’t add back.
- Skipping surface prep so adhesive won’t bond.
- Ignoring the sweep/threshold; most leaks are at the bottom.
- Trying to “seal” a warped or out-of-square door without fixing alignment first.
When to call a pro
- The door is badly out of square, rubbing, or has frame rot.
- You have a commercial steel frame or specialty fire-rated door that needs code-compliant gasketing.
- The threshold is damaged or you need sill pan or rot repairs.
- You’ve tried proper seals, but the door still won’t latch without force.
With the right materials and careful fitting, most homeowners can refresh a door’s weather stripping in under an hour. Start with a good match to your existing system, aim for uniform light compression, and finish with a sweep/threshold tune-up for a draft-free entry.